Here's a collection of vero (stripboard) and tagboard guitar and bass effect layouts that we have put together covering many classic and popular effects in growing numbers. Many of these have been posted on freestompboxes.org, so check that site out for great discussions on building your own effect pedals. Enjoy the builds and please also visit us on Facebook and Twitter

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Sunday, 27 November 2016

Charge Pump Extravaganza

Here's something I've been looking for for awhile now for a project I've got in the works, and figured some of you guys may be looking for the same thing. They're based off of the schematic published by the one and only R.G. Keen, found here.

Layout 1: +9V to +17V

Layout 2: +9V to +25V

Layout 3: +9V to +33V

Remember to watch your electrolytics voltage rating, especially with the +33V charge pump
Note: You can NOT substitute the MAX1044 for 7660s or NE555 IC.

Here's the problem I see on the 17V layout. One of the 10uF caps should connect between the junction of D1 and D2 to pin 2 of the IC. The cathode of D2 will then be 17V. Likewise there should be a 10uF cap between the junction of D3 and D4 and pin 2. The cathode of D4 will then be 25V.

The 33V layout has the same connection issues, I don't see any caps connected to the junctions of the diode pairs. But it should correctly output 33V.

I´ve been looking for charge pumps that could supply more that 18v from a 9v source with no success, so thanks so much!Could I just throw the 33v charge pump inside a fet build, (let´ say sunn mode T preamp), without damaging the transistors?

Just personal experiences. Opamp based circuits rarely sound any different when fed anything from 5V to 18V. The headroom you were expecting could be achieved by using a swing of +9V/-9V or +12V/-12V, like seen in Maxon OD820 and the like.

So to my knowlwdge, there is little to no point in using a pump with standard tubescreamer circuit. I've tried it myself back in the day too. If you have a lab supply, you could try the circuit without a pump and change the supply voltage gradually from 5V to 18V. I can tell you the difference in tone is not that audible at all. Well. Perhaps some other type of opamp could behave differently with higher Vcc, but i doubt it.

In other words, your behaviour is expected. And a feature of basic opamp. But. There is a certain "mojo" to pump the voltage. IMO, you should try to flip the pedal for big bucks and use the "internal 18V operation" as a selling point. No difference in sound, but notable difference in actual selling price :)+m

A number of people have asked me to do a build guide for one of these effects, but I noticed the other day that one of the guys here (timmy)...

Note

Not all these layouts are verified and some are put together from unverified schematics. So if you have good luck, or bad luck for that matter, then please let me know by dropping a comment in the topic. Thanks.

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